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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

    <script>

        // var obj = {
        //     name : 'yy' , 
        //     age : 18
        // }


        // obj.sex = '女' ;

        // console.log(obj);



        // 对象的自定义属性

        var arr = [1,2,3] ;
        // console.log(arr[100]);
        // console.log(arr.qq);

        arr.qq = 666 ;   // 

        console.log(arr.qq);

    </script>
    
</body>
</html>